lauraleespears1,
I am sorry to hear about your son's illness and hope he is doing well.
Calcium deposits form on all homografts, it is just a matter of time. They may form faster in some people than others, but there is no way to predict who those people are.
The reason your doctor never mentioned any vitamins to you is because there is no randomized study to show that any vitamins significantly reduce calcium deposit. Vitamin companies do not do randomized trials like pharmaceutical companies and do not need FDA backing to release their product. For some reason, people still spend billions on vitamins that are not proven to help. From the manufacturer stand point, why should they spend the money if people still by them without the studies.
I hope this helps and good luck!
look into this stuff